This is a annoyance that causes me to lose mail and repeat email entry. Often, when I try to write a message, Thunderbird freezes as I type and the active window jumps back and forth between the compose email window and the main Thunderbird window. It eventually returns to the compose email window, but not before I have typed a significant amount on the main Thunderbird window, causing emails to disappear (and not be in deleted or junk folders), threads to disappear, emails to be deleted or marked as spam (different from the issue above) or mark as read, change folder and then to go back to writing my email as if nothing happened except that a stretch of what I wrote is missing. It is important enough that I am writing this - something I do before I decide to make major changes in the hope that this can be fixed so that I don't have to. Any ideas what I can do to resolve this issue?